Image manipulation in Python.

Image_Manipulation.py

import pygame, sys
from pygame.locals import *
pygame.init()

grey = (150, 150, 150)
lite_grey = (220, 220, 220)
blue = (80, 144, 154)
dark_blue = (0,50,77)
lite_blue = (143,220,236)

display_surface = pygame.display.set_mode((900,948))
display_surface.fill(grey)

image = pygame.image.load("image_before.png").convert()

for x in range(900):
     for y in range(948):
        color_temp = image.get_at((x,y))
        temp_int = color_temp[0] + color_temp[1] + color_temp[2]

integer = (max(color_temp[0], color_temp[1], color_temp[2]) + temp_int//2//3)

if integer < 70:
     image.set_at((x,y),dark_blue)
elif integer < 100:
     image.set_at((x,y),blue)
elif integer < 130:
     image.set_at((x,y),lite_blue)
else:
     image.set_at((x,y),lite_grey)

pygame.image.save(image, 'image_after.png')

while True:
     for event in pygame.event.get():
        if event.type == QUIT:
        pygame.quit()
        sys.exit()

        display_surface.blit(image, (0,0))
        pygame.display.update()